Delta Air Lines reported another quarterly loss Thursday to conclude what its CEO called "the toughest year in Delta's history" following the hit from the coronavirus pandemic.

Amid depressed traffic levels, Delta's loss for all of 2020 was $12.4 billion, compared with profits of $4.8 billion in 2019.

The loss again highlights the brutal impact of the pandemic on commercial plane travel. However, executives are more optimistic about the year ahead thanks to Covid-19 vaccines.

"Our December quarter capped the toughest year in Delta's history," said Chief Executive Ed Bastian said in a statement.

"While our challenges continue in 2021, I am optimistic this will be a year of recovery and a turning point that results in an even stronger Delta returning to revenue growth, profitability and free cash generation."

Delta Air Lines reported a huge loss for 2020 due to the coronavirus, but expects an improving market in 2021
Delta Air Lines reported a huge loss for 2020 due to the coronavirus, but expects an improving market in 2021 GETTY IMAGES NORTH AMERICA / Christian Petersen

Airlines have laid off thousands of workers and taken planes out of service in an effort to curtail costs during the prolonged downturn.

The big US carrier suffered a $755 million loss in the fourth quarter as revenues plunged 65 percent to $4.0 billion.

Delta said its cash burn in the fourth quarter was $12 million daily day, an improvement on the third-quarter daily burn rate of $24 million.

The company expects "three distinct phases" of recovery in 2021, said President Glen Hauenstein, with a "choppy demand recovery" early in the year, followed by an inflection point and then a "sustained demand recovery as customer confidence gains momentum, vaccinations become widespread and officers reopen."

Shares of Delta rose 2.9 percent to $41.60 in pre-market trading.

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